s908ey16g2vfar Freescale Semiconductor, Inc, s908ey16g2vfar Datasheet - Page 243

• Manufacturer Part Number: s908ey16g2vfar
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Enter monitor mode with pin configuration shown in
rising edge of RST latches monitor mode. Once monitor mode is latched, the levels on the port pins
except PTA0 can change.
Once out of reset, the MCU waits for the host to send eight security bytes (see
security bytes, the MCU sends a break signal (10 consecutive 0s) to the host, indicating that it is ready to
receive a command.
19.3.1.1 Normal Monitor Mode
If V
the input clock.
When monitor mode was entered with V
as long as V
This condition states that as long as V
V
then the COP will be disabled. In the latter situation, after V
removed from the IRQ pin in the interest of freeing the IRQ for normal functionality in monitor mode.
Freescale Semiconductor
TST
2
3
5
1 μF
1 μF
TST
DB9
is applied to RST after the initial reset to get into monitor mode (when V
is applied to IRQ upon monitor mode entry, the internal operating frequency is a divide-by-four of
+
+
7
8
1
3
4
5
TST
C1+
C1–
C2+
C2–
While the voltage on IRQ is at V
external square-wave clock becomes the clock source. Dropping IRQ to
below V
source selected by the ICG (a determined by the settings in the ICG
registers).
is applied to either IRQ or RST.
MAX232
TST
GND
V
V+
V–
CC
Figure 19-11. Forced Monitor Mode (V
MC68HC908EY16A • MC68HC908EY8A Data Sheet, Rev. 1
will remove the bypass and the MCU will revert to the clock
16
15
2
10
6
9
V
DD
+
+
1 μF
1 μF
2
74HC125
TST
1
+
TST
3
1 μF
is maintained on the IRQ pin after entering monitor mode, or if
74HC125
on IRQ, the computer operating properly (COP) is disabled
6
TST
4
NOTE
, the ICG module is bypassed and the
5
Table 19-1
V
DD
10 kΩ
TST
is applied to the RST pin, V
by pulling RST low and then high. The
10 k*
N.C.
N.C.
IRQ
= V
RST
OSC1
IRQ
PTA0
SS
)
MC68HC908EY16A/8A
TST
19.3.2
was applied to IRQ),
Monitor Module (MON)
Security). After the
PTB4
PTB3
PTA1
V
V
V
V
DDA
SSA
DD
SS
TST
10 k
can be
V
DD
N.C.
N.C.
0.1 μF
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